The invention relates to a vehicle seat.
Such a vehicle seat comprises a seat part for providing a seat surface for a seat occupant, a guide track arrangement for the longitudinally adjustable arrangement of the vehicle seat in a vehicle and a height adjustment device for adjusting the seat height of the vehicle seat. The height adjustment device comprises a plurality of rockers which are pivotably coupled to the seat part and the guide track arrangement, wherein said rockers connect the seat part to the guide track arrangement so as to be adjustable in height. In order to drive a first of these rockers and furthermore to adjust the seat part relative to the guide track arrangement for the purpose of seat height adjustment the height adjustment device comprises an electromotive drive unit, which comprises an output pinion, which engages in a toothing of a tooth segment and can be rotated in respect to the tooth segment for adjusting the seat height.
In case of a conventional vehicle seat of this kind, the tooth segment is connected to the first rocker and is moved by a drive unit connected to the seat part or the guide track arrangement. The drive unit drives hereby an output pinion engaging in the tooth segment and exerts in this manner an adjustment force onto the first rocker connected to the tooth segment. Since the output pinion unrolls on the tooth segment the first rocker and together therewith also the remaining rockers according to the type of a four joint is pivoted such that the seat part is adjusted in the seat height thereof.
In case of a vehicle seat known from EP 0 366 364 B1 a pinion is arranged on a side part of a seat part and engages in a tooth segment formed in one piece on a rocker. The pinion can be manually rotated for adjusting the height of the vehicle seat in order to pivot the assigned rocker in this manner. Additionally, the inclination of the seat part can be adjusted by engaging a pinion arranged on the rocker in a tooth segment on a guide track arrangement.
In case of a vehicle seat known from U.S. Pat. No. 4,229,041 a seat frame of a seat part is mounted pivotably on a guide track arrangement. A pinion arranged on the seat frame engages in a tooth segment arranged on the guide track arrangement and can be rotated for pivoting the seat frame relative to the guide track arrangement for the purpose of adjusting the height of the seat part.
A vehicle seat is known from FR 2503061 in which a seat part is connected pivotably to a guide track arrangement and the inclination thereof can be adjusted by a pinion engaging in a tooth segment on the guide track arrangement.
In conventional vehicle seats, which use electromotive drives for a height adjustment device, the drive is arranged usually on the side of the vehicle seat facing the vehicle door, where sufficient construction space for connecting the drive to the seat part or to the guide track arrangement is available. If however the drive shall be arranged at the so called tunnel side of the vehicle seat situated towards the vehicle centre, then a tight connection of the drive to the seat part or the guide track arrangement may be difficult, since on this side of the vehicle seat less construction space is available and in particular an arrangement of the drive outside of the seat part or the guide track arrangement is not possible. An arrangement of a drive on said tunnel side can however be desirable, if, e.g., a belt attachment point for attaching a seat belt at the tunnel side on the seat part shall be provided. In this case the tunnel side of the vehicle seat is subjected in case of a crash to high loading forces, which can be supported and dissipated by the drive unit arranged on the tunnel side and engagement of the output pinion in the tooth segment at the driven rocker. The requirements for rigidity and crash stability of the output pinion-tooth segment-engagement via which the driven rocker and thus the seat part is retained altogether in position are high in this case and have to be designed for loading forces dissipating in a crash case via the belt attachment point on the tunnel side into the seat part.